CN2660236Y - Device of increasing magnetic liquid sealing pressure durable abilities of reciprocating shaft - Google Patents

Abstract

A device is used to improve the sealing pressure capacity of magnetic liquid of reciprocating axis. In assembly, a bearing (3), a pole shoe (6) inlaid with a rubber seal ring (5) and a permanent magnet (7) are arranged on the right side of an internal cam of a sleeve (2) and a magnetic liquid (9) is injected among pole teeth of the pole shoe (6); then a pole shoe (8) inlaid with the rubber seal ring (5) is arranged and the magnetic liquid (9) is injected among pole teeth of the pole shoe (8); and a bearing (10), a regulating gasket (11) and a ring flange (13) are fixed by a bolt (12) for compacting the above parts; finally, a shaft (14) coated with a nano anti-friction membrane (4) is arranged. The utility model has the advantages that the sealing pressure capacity of the magnetic liquid is increases, the leakage rate is less than 10<-11>pa1.m-11/s, and the service life is extended.

Description

A device for improving the pressure resistance capacity of the reciprocating shaft magnetic liquid seal

technical field

The utility model belongs to the technical field of mechanical engineering seals, and is particularly suitable for magnetic liquid seals of reciprocating shafts.

Background technique

The reciprocating shaft magnetic liquid seal is different from the rotating shaft magnetic liquid seal, and its sealing pressure resistance is affected by the friction between the reciprocating shaft and the magnetic liquid. The existing reciprocating shaft is made of magnetically conductive material, generally No. 45 steel, and the magnetic liquid has certain wettability on the surface of No. 45 steel. As the speed increases, the shear rate between the reciprocating shaft and the magnetic fluid increases, and so does the friction. When the friction force is large, the amount of magnetic liquid taken away by the reciprocating shaft during reciprocating motion is large, and the deformation of the magnetic liquid in the pole tooth gap increases, which makes the magnetic field strength value on both sides of the magnetic liquid film decrease, resulting in the pressure resistance of the sealing device. capacity decline, or even failure.

Contents of the invention

The technical problem to be solved by the utility model is that the frictional force between the existing reciprocating shaft magnetic liquid seal shaft and the magnetic liquid is relatively large, resulting in a decrease in the pressure resistance of the sealing device, or even failure. Devices that are sealed against pressure.

The technical scheme of the utility model: the surface of the reciprocating shaft is coated with a nano-friction-reducing thin film coating, so that the friction between the magnetic liquid and the reciprocating shaft is greatly reduced, so that the deformation of the magnetic liquid is small and the pressure resistance is greatly improved.

The device for improving the pressure resistance of the magnetic liquid seal of the reciprocating shaft includes: sleeves, bearings, rubber sealing rings, permanent magnets, pole pieces, nano-friction-reducing films, magnetic liquids, screws, adjusting gaskets, flanges, and shafts. A groove with a depth of 0.1mm is processed on the surface of the corresponding position of the shaft between the outer end faces of the two bearings, and a nano-friction-reducing film of polytetrafluoroethylene material with a thickness of 0.1mm is plated on the groove. When installing, first insert the rubber sealing ring into the pole piece, then install the bearing, the pole piece with the rubber sealing ring embedded and the permanent magnet on the right side of the inner boss of the sleeve, inject the magnetic liquid between the pole teeth of the pole piece, and then Install the other pole piece with the rubber sealing ring embedded, inject magnetic liquid between the pole teeth of the pole piece, then install another bearing, adjusting gasket and flange, fix them with screws, and press the above parts tightly , and finally install the shaft coated with nano-friction-reducing film. Under the action of the magnetic field, the magnetic liquid is adsorbed in the gap between the pole teeth of the pole piece to form a reliable seal.

The beneficial effect of the utility model is that, after the surface of the reciprocating shaft is coated with a layer of nano-friction-reducing film coating, the pressure resistance of the magnetic liquid is improved, and the leakage rate of the device is lower than 10 ^-11 pal·m ³ /s. Life extension.

Description of drawings

Figure 1 Structural diagram of the device for improving the pressure resistance capacity of the reciprocating shaft magnetic liquid seal

Figure 2A enlarged view of local structure

In the figure: threaded hole 1, sleeve 2, bearing 3, nano anti-friction film 4, rubber sealing ring 5, pole shoe 6, permanent magnet 7, pole shoe 8, magnetic liquid 9, bearing 10, screw 11, adjusting gasket 12 , Flange 13, shaft 14.

Detailed ways

The utility model is further described with accompanying drawing as specific embodiment:

The device for improving the pressure resistance capacity of the magnetic liquid seal of the reciprocating shaft includes: sleeve 2, bearing 3, nano-friction-reducing film 4, rubber sealing ring 5, pole shoe 6, permanent magnet 7, pole shoe 8, magnetic liquid 9, bearing 10, screws 11. Adjust gasket 12, flange 13, shaft 14. When installing, first insert the rubber sealing ring 5 into the pole shoe 6 and the pole shoe 8, and then install the bearing 3, the pole shoe 6 with the rubber sealing ring 5 embedded and the permanent magnet 7 on the right side of the inner boss of the sleeve 2 in sequence, and place the The magnetic liquid 9 is injected between the pole teeth of the pole shoe 6, and then the pole shoe 8 embedded with the rubber sealing ring 5 is installed, and the magnetic liquid 9 is injected between the pole teeth of the pole shoe 8, and then the bearing 10 and the adjusting gasket are installed 11 and flange 13 are fixed with screws 12, and the above parts are compressed, and finally the shaft 14 coated with nano-friction-reducing film 4 is loaded onto. The magnetic liquid 9 is adsorbed in the tooth gap between the pole piece 6 and the pole piece 8 under the action of the magnetic field to form a reliable seal.

On the surface of the corresponding position of the shaft 14 between the left end surface of the bearing 3 and the right end surface of the bearing 10, a groove with a depth of 0.1mm is processed, and a nanometer layer of polytetrafluoroethylene material with a thickness of 0.1mm is plated on the groove. Anti-friction film 4, because polytetrafluoroethylene has non-stick properties, so the amount of magnetic liquid taken away by the shaft coated with polytetrafluoroethylene during reciprocating motion is very small, so that the friction between magnetic liquid 9 and reciprocating shaft 14 The force is greatly reduced, and the deformation of the magnetic fluid is small, thereby improving the pressure resistance of the magnetic fluid.

The adjusting gasket 11 is used for adjusting the axial distance during assembly. Threaded hole 1 is designed for connecting with other devices.

Cover 2, adjusting gasket 11 and screw 12 are all made of non-magnetic material, such as stainless steel. The material of the shaft 14 is made of a magnetically permeable material, such as No. 45 steel.

The structure of pole piece 6 and pole piece 8 is symmetrical. A groove for placing rubber sealing ring 5 is arranged on the outer cylindrical surface. A boss is designed on both sides of pole piece 6 and pole piece 8. The function of one boss is to isolate the magnetic circuit. Prevent the magnetic liquid 9 from being adsorbed to the bearing 3 or the bearing 10; the other boss is the position for fixing the permanent magnet 7. The pole shoe 6 and the pole shoe 8 are made of electrical pure iron.

Bearing 3 and bearing 10 are of the same type.

Permanent magnet 7 selects NdFeB or SmCo or AlNiCo material according to the requirements of actual temperature, selects NdFeB at room temperature, selects SmCo when the temperature is below 300°C, and selects AlNiCo when the temperature is below 400°C.

The type of magnetic liquid can be selected according to the difference of sealing gas and temperature environment, and the magnetic liquid of different base liquid can be selected and injected at one time during assembly.

The number of stages of pole teeth is determined according to the pressure difference condition of the seal, and the sealing capacity of each stage is 0.5 atmosphere. The gap between the pole piece and the shaft is 0.1-0.2mm, the tooth width of the pole teeth is 3-5 times of the gap, and the tooth height is 20-30 times of the gap.

Example of use: Carry out a vacuum seal design for a reciprocating shaft with a diameter of 50 mm. On the surface of the corresponding position of the shaft between the outer end faces of the two bearings, process a groove with a depth of 0.1 mm, and coat a layer with a thickness of 0.1 mm on the groove. mm PTFE material nano-friction-reducing film, using 6-stage pole tooth seal, the gap between the pole shoe and the shaft is 0.1mm, the tooth width is 0.5mm, and the tooth height is 2.5mm. 5ml of kerosene-based magnetic liquid is injected into the permanent magnet. Use NdFeB material. When the stroke of the reciprocating shaft is 200mm and the speed is 200rpm, the detected gas leakage rate during use of the device is less than 10 ^-11 pal·m ³ /s, and the running time is as long as 1080 hours.

The sealing device is also suitable for positive pressure sealing.

Claims (1)

1. A device for improving the pressure resistance of magnetic liquid seals of reciprocating shafts, the device comprising: sleeves, bearings, rubber sealing rings, pole shoes, permanent magnets, magnetic liquid, screws, adjusting gaskets, flanges, and shafts; The feature is that, on the corresponding position surface of the shaft (14) between the left end surface of the bearing (3) and the right end surface of the bearing (10), a groove with a depth of 0.1 mm is processed, and a layer with a thickness of 0.1 mm is plated on the groove. mm of polytetrafluoroethylene material nano-friction-reducing film (4).